The present invention relates to an imaging device, such as a digital still camera and a digital video camera, and signal processing.
In a solid state image sensor, such as a complementary metal oxide semiconductor (CMOS) image sensor, which attains an increased number of pixels, addition reading or thin-out reading has been used as a technique of performing high frame rate reading.
Among these techniques, the addition reading method has been commonly used because of its advantage of increasing a signal to noise ratio (also referred to as an SN ratio hereinafter).
Using the addition reading, however, naturally causes lowering the resolution compared to a method of reading all the photo receiving pixels separately.
Meanwhile, folding distortion may occur more frequently in image data obtained by the thin-out reading method than in the addition reading method. Accordingly, however, an effect of improving the resolution increases by a technology such as super resolution technology.
An SN ratio, however, is more largely reduced when the thin-out reading is used than using the addition reading. Deterioration of the SN ratio may stand out very much particularly when the intensity of illumination is low.
It has been proposed, therefore, to switch between the thin-out reading and the addition reading, as needed, to thereby balance between resolution and SN ratio (see Patent Document 1).
In another approach, an imaging device which includes a color filter array of a novel color arrangement to allow increase of sensitivity with the minimum decrease in resolution has also been proposed (see Patent Documents 2 and 3).